Cabin noise reduction in the DC-9

1967 ◽  
Author(s):  
M. BALLARD
Keyword(s):  
2018 ◽  
Vol 66 (4) ◽  
pp. 362-374 ◽  
Author(s):  
Ying Hu ◽  
Chenxi Li ◽  
Feng Han ◽  
Zixin Feng ◽  
Liyan He

2013 ◽  
Author(s):  
Ninad Pimpalkhare ◽  
Gaurav Gupta ◽  
Mugundaram Ravindran ◽  
Chetan Prakash Jain ◽  
Chiranjit Ghosh ◽  
...  

Author(s):  
Jee-Hun Song ◽  
Suk-Yoon Hong ◽  
Hyun-Wung Kwon
Keyword(s):  

2001 ◽  
Vol 38 (1) ◽  
pp. 164-173 ◽  
Author(s):  
A. Grewal ◽  
D. G. Zimcik ◽  
B. Leigh

2018 ◽  
Vol 2018 ◽  
pp. 1-10
Author(s):  
Linus Yinn Leng Ang ◽  
Le Quan Ngoc Tran ◽  
Steve Phillips ◽  
Yong Khiang Koh ◽  
Heow Pueh Lee

Soldiers and supporting engineers are frequently exposed to high low-frequency (<500 Hz) cabin noise in military vehicles. Despite the use of commercial hearing protection devices, the risk of auditory damage is still imminent because the devices may not be optimally customised for such applications. This study considers flax fibre-reinforced polypropylene (Flax-PP) as an alternative to the material selection for the ear cups of commercial earmuffs, which are typically made of acrylonitrile butadiene styrene (ABS). Different weaving configurations (woven and nonwoven) and various noise environments (pink noise, cabin booming noise, and firing noise) were considered to investigate the feasibility of the proposed composite earmuffs for low-frequency noise reduction. The remaining assembly components of the earmuff were kept consistent with those of a commercial earmuff, which served as a benchmark for results comparison. In contrast to the commercial earmuff, the composite earmuffs were shown to be better in mitigating low-frequency noise by up to 16.6 dB, while compromising midfrequency acoustical performance. Consequently, the proposed composite earmuffs may be an alternative for low-frequency noise reduction in vehicle cabins, at airports, and at construction sites involving heavy machineries.


Author(s):  
Zeyu Shi ◽  
Xiongliang Yao ◽  
Guoxun Wu ◽  
Yue Tian

The noise of ship structure is mainly transmitted by two types which are air sound and structural sound. As a kind of mechanical energy, sound is produced by the sound source and goes through various transmission paths to the recipient. This process is a process of constant loss of energy. Therefore, according to aspects of noise generation, output, transmission and reception, the principle of cabin noise control can be divided into four aspects which are cabin structure acoustics design, noise source control, noise transfer path and individual protection at the end of cabin. In order to determine the best noise reduction measures, noise control measures should be considered on the basis of three principles of science, advanced nature and economy. Statistical energy analysis (SEA) graph method is compared a series of adjacent loss factor matrices in the SEA model with the data structure of graphs in graph theory, a plurality of transmission path of SEA model can be obtained by giving different weights to adjacent matrix loss factor matrices in SEA model. The problem of finding maximum energy transfer path in the SEA model is actually equivalent to the issue of seeking shortest path in the graph theory. In order to reduce the cabin noise of the ship structure, it is necessary to know the main source and the main energy conduction path of the noise cabin. The problem is translated into K shortest path problem in graph theory. In this paper, acoustical sensitivity analysis of noise reduction design parameter is developed according to sound energy transmission of two layer cavities structure, which can guide the noise reduction design of the ship cabin. The proposed cabin noise control method is applied to the problem of overproof cabin noise, and the optimal noise control scheme is obtained.


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